A private branch exchange (“PBX”) is a telephone network that serves a business or an office. A virtual PBX (“vPBX”) allows a business or office to be served by a PBX system hosted on remote servers. The service is provided through a combined voice network (e.g., telephone network) and data network (e.g., Internet). A vPBX typically involves one or more voice-over-IP (“VOIP”) servers, a call management program, a network, a gateway that links the voice network and data network, and one or more extensions. In a conventional vPBX system, the servers and gateways are usually unaware of the geographical location of the extensions. Therefore, conventional vPBX systems are not well suited to routing and controlling calls based on geographic locations of mobile devices connected to the vPBX system.